1. Field of the Invention
The present invention relates to air filter for a vehicle ventilating or air conditioning unit.
2. Description of the Related Art
It is now common to provide passenger vehicles such as cars with air conditioning units. Such units typically comprise a housing having a first inlet in use disposed in communication with the interior of the vehicle passenger compartment and a second air inlet for inducing ambient air. The housing contains an evaporator whose function is to cool the air which enters via one or other of the inlets, and the housing has an air outlet for cooled air. As is known to those skilled in the art, the cooled air is usually passed to a heating and distribution unit for supply to different openings within the passenger compartment.
When air of high humidity is passed through the cooling evaporator, the moisture in the air condenses out and it is therefore necessary to provide a liquid outlet downstream of the evaporator, and normally near to or in the bottom wall of the housing so that the condensate can be suitably disposed of.
Air conditioning units are of particular utility in high temperature high humidity parts of the world, for example tropical parts of the world. A difficulty may arise when high rainfall leads to water being induced through the external air inlet. Unless a technique is devised for guiding water induced in this way out of the air conditioning unit, the water will collect in the housing and stagnate thereby giving rise to smells, will prevent the filter member from working properly or may eventually leak into the passenger compartment.
It is accordingly an object of the present invention to provide an air conditioning unit which is capable of coping with incoming rain.
According to a first aspect of the present invention there is provided an air filter assembly for a motor vehicle comprising filter housing and an air filter, the filter housing having an air inlet and an air outlet, the air filter being disposed in said filter housing, and the housing having at least one liquid outlet downstream of the filter wherein the assembly has a filter bypass passageway for enabling liquid entering at said air inlet to flow past said filter to said liquid outlet.
Preferably, the filter housing further comprises an evaporator disposed downstream of the filter.
Preferably the housing has a lower wall and the air filter has a lower portion spaced from the lower wall to define said passageway therebetween.
Advantageously the air filter has a total area more than 10 times the area of said passage.
Conveniently the filter assembly has an upper wall, opposing sidewalls and a lower wall, said lower wall defining an opening therein, a filter module having a portion extending through said opening, the filter module further having a face plate sealingly abutting an outer face of said lower wall, said filter module comprising a frame having an outer perimeter portion engaging the sidewalls and said upper wall, said frame supporting a filter member spaced from said lower wall to define said passage.
Advantageously said frame comprises a transverse web spaced from the face plate and defining therebetween a through hole.
Conveniently the air conditioning unit further comprises plural supporting web portions disposed between the face plate and said transverse web.
Preferably the filter member has a total area more than 30 times the area of said passage.
Preferably the outer perimeter portion has an outwardly-directed flange portion and the housing has a counterpart slot. Preferably the lower wall has a depressed region forming a trough.
Conveniently said trough is substantially filled with a closed foam material.
Advantageously said closed foam material comprises liquid guide passageways for directing the liquid to said liquid outlet.
An embodiment of the invention will now be described by way of example only, with respect to the accompanying drawings in which: